use expect for file contents

[hf24601]

I would like to use expect to parse through the contents of a file, something like this:

spawn cat log/mylog.txt
expect {
-re "some_expr" { ...do something... }
default { ...do something else... }

Note that I am simply reading a file, so there is nothing really interactive going on. Even so, this works most of the time, but sometimes I think that expect gets ahead of itself and tries to read the file contents before they are ready, and I get failed tests.

Is there some convenient way to use the spawn/expect sequence for reading through a file? Is there any easy way to force expect to wait until the spawn is completed?

Spawn/expect are designed for interactive use. Since I am mostly non-interactive, is there a better way to do this than the approach I am taking?

Thanks in advance.

 

[ExpectTheUnexpected]

set file log/mylog.txt
if {[catch {open $file} input] == 1} {
puts "File not found!"

} else {
while { [gets $input line] != -1 } {

puts $line
if {[regexp "some_expr" $line] == 1 } {
puts "some_expr found in the file!"
}
}
}